/*
 *	Generate the syscall functions for Z88DK
 *
 *	SCC has some "interesting" properties. It's SmallC derived so pushes
 *	the arguments backwards which we must cope with while the kernel API
 *	carefully matches the gcc API of argument 1 in x and the other
 *	arguments on the stack offset as needed for the caller of the syscall
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "syscall_name.h"

static char namebuf[128];

static void write_call(int n)
{
  FILE *fp;
  snprintf(namebuf, 128, "fuzix-scc6809/%s.s", syscall_name[n]);
  fp = fopen(namebuf, "w");
  if (fp == NULL) {
    perror(namebuf);
    exit(1);
  }
  
  fprintf(fp, "\t.text\n");
  fprintf(fp, "\t.extern __syscall\n");
  fprintf(fp, "\t.globl %s\n\n", syscall_name[n]);
  fprintf(fp, "%s:\n", syscall_name[n]);

  if (syscall_args[n] == VARARGS) {
    /* Icky but there are only 3 and all are 2 v 3 arg */
    fprintf(fp, "\tcmpu #2\n");
    fprintf(fp, "\tbne l1\n");
    fprintf(fp, "\tpuls d,x,u\n");
    fprintf(fp, "\texg x,u\n");
    fprintf(fp, "\tpshs d,x,u\n");
    fprintf(fp, "\tldx 6,s\n");
    fprintf(fp, "\tldd #%d\n", n);
    fprintf(fp, "\tjmp __syscall\n");
    fprintf(fp, "l1:\n");
    fprintf(fp, "\tpuls d,x,y,u\n");
    fprintf(fp, "\texg x,u\n");
    fprintf(fp, "\tpshs d,x,y,u\n");
    fprintf(fp, "\tldx 8,s\n");
    fprintf(fp, "\tldd #%d\n", n);
    fprintf(fp, "\tjmp __syscall\n");
    fclose(fp);
    return;
  }

  switch(syscall_args[n]) {
    case 0:
      break;
    case 1:
      fprintf(fp, "\tldx 2,s\n");
      break;
    case 2:
      fprintf(fp, "\tldx 4,s\n");
      break;
    case 3:
      fprintf(fp, "\tpuls d,x,u\n");
      fprintf(fp, "\texg x,u\n");
      fprintf(fp, "\tpshs d,x,u\n");
      fprintf(fp, "\tldx 6,s\n");
      break;
    case 4:
      fprintf(fp, "\tpuls d,x,y,u\n");
      fprintf(fp, "\texg x,u\n");
      fprintf(fp, "\tpshs d,x,y,u\n");
      fprintf(fp, "\tldx 8,s\n");
  }
  fprintf(fp, "\tldd #%d\n", n);
  fprintf(fp, "\tjmp __syscall\n");
  fclose(fp);
}

static void write_call_table(void)
{
  int i;
  for (i = 0; i < NR_SYSCALL; i++)
    write_call(i);
}

static void write_makefile(void)
{
  int i;
  FILE *fp = fopen("fuzix-scc6809/Makefile", "w");
  if (fp == NULL) {
    perror("Makefile");
    exit(1);
  }
  fprintf(fp, "# Autogenerated by tools/syscall-scc6809\n");
  fprintf(fp, "CROSS_AS=lxas09\nCROSS_LD=lxld09\nCROSS_AR=lxar\n");
  fprintf(fp, "ASYS=syscall$(PLATFORM).s\n");
  fprintf(fp, "ASRCS = syscall_%s.s\n", syscall_name[0]);
  for (i = 1; i < NR_SYSCALL; i++)
    fprintf(fp, "ASRCS += syscall_%s.s\n", syscall_name[i]);
  fprintf(fp, "\n\nASRCALL = $(ASRCS) $(ASYS)\n");
  fprintf(fp, "\nAOBJS = $(ASRCALL:.s=.o)\n\n");
  fprintf(fp, "syslib.lib: $(AOBJS)\n");
  fprintf(fp, "\techo $(AOBJS) >syslib.l\n");
  fprintf(fp, "\t$(CROSS_AR) rc syslib.lib $(AOBJS)\n\n");
  fprintf(fp, "$(AOBJS): %%.o: %%.s\n");
  fprintf(fp, "\t$(CROSS_AS) $(ASOPTS) -o $*.o $<\n\n");
  fprintf(fp, "clean:\n");
  fprintf(fp, "\trm -f $(AOBJS) $(ASRCS) syslib.lib syslib.l *~\n\n");
  fclose(fp);
}

int main(int argc, char *argv[])
{
  write_makefile();
  write_call_table();
  exit(0);
}
